NATIONAL TRAXSFQRTATION S A K T i WARD DEpARlMENT OF TRANSPORrATION AIECRAFP ACCIDENT REWRT

AERO C O W D F I I 1121, N23GTp THE PITTSTON COf4PANY

TABLF OF CONTENTS

Synorsis........... ......................... Probable Cause ..............................

1.1 History of Flight.....,..... ................ 1.2 Injwies to Persons.. ....................... 1.3 h g e to Aircraft.......................... 1.4 Other Damsge. ............................... 1.S Crew Information.. .......................... 1.6 Alrcraf’t Information.. ...................... 1.7 Meteorological Information..................

1.9 Communications.............................. 1.8 Aids to Navigation..

1.10 Aerodrune and GrDund Facilities.,........... 1.ll Flight.Recorders............................ 1.22 Aircraft Wreckage........................... 1.13 Fire ........................................ 1.3.4 Survival AspectE.. .......................... 1.3.5 Tests and Research .......................... 2.1 Analysis...................... 1.l6 Pertinent Information..

2.2 Conclusions .................................

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..................... .............. ........................ .................... I a) Findings..

b) Probable Cause 3. Recomnendatlo3..............................

Appendix

a 1 1 2 3 : 4 5 6 5

6 6 6

11 7

ll ll 12 12 15 15 16 16

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i

F i l e No. 3-4110

Adopted: September 9. 1970 -

AERO C-DER ll21. N36JP THE PITTSTON COWANY

I i U k RETFFAT, VhGIkUl OCTOBER 3, 1969

SYWOFSIS

Yhe P i t t s ton Compaw's Aero CamawlerA&& from LaCuardia Airport, New york, t o Tri-City Airport, Johnson City,

N236Jp, on a f l i g h t

Tennessee, on the night of October 31, 1969, crashed a t approxiuately 2210 e.s.t. while descending on a radar vector t o the final approach COLE& at Tri-City. The crew of two and the one passenger aboard the a i r c r a f t were f a t a l l y iqlured.

l eve l while in an approximately 60" nosedown wings-level a t t i tude. The a i r c r a f t made contact w i t h the ground 2,450 fee t above sea

The impact site was about 2 miles northeast of Mountain h p i r e Airport, Rural Retreat, Virginia. The impact cra ter was 25 f e e t i n diameter at the top, with a depth of about 18 fee t . The l e f t a i leron was the

r a a i n d e r of the wreckage was below the loose d i r t at the 9-fOot l e v e l only la rge piece of the a i r c r a f t that was v i s ib le i n the cra ter . The

or strewn forward along both s ides of a wreckage psth that extended 500 f e e t beyonC the cra ter .

.The h r d determines tha t the probable cause ,of this accident was that , follcwing a malfunction w a e Ln th. Ufi-volt alter- natl.ng cwran t el.ecLr-c.d-system, t h e s w did not. take proper acsgon, r e s u l t l t g in tke of the p i l o t ' s f l iRht i n s t ~ n ~ t s in~inst rument ..._ fiiAht .cQait ioxs and subsequent loss of control.

The Board recumnends t h a t the Administrator, ?ederal Aviation

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Administration, take necessary action t o e.ss1n-e t h a t all avionics mo?ifications t 3 a i rc ra f t , and t h e i r proper use, be documented as amendments t o the maintenance and flight uanuals, and t h a t t h i s in- formation be di3seninated t o a i r c r d t owners and pi.lots.

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1. INV3STIGATION

1.1 History of Flikht

N23&L~n Aero Ccmuna nder Model ll21 turbo-Jet, was operated by T h e m t o n ComDany. 250 Park Avenue. New York. N. Y. 14607. a s an erecutive &t in the conduct of impany buiiness. On the night of October 3. 1969. two ComDanv Dilots. with a comaaw emnlovee as a

..

(IS7 E l . The f l i g h t cieparted a t 2042 e.s.t. y o n an Instrument Fl ight Rules

or the following route o f f n g h t :

vector 't.0 Sparta, N. J.,VORPAC, l l g " radia l t o Sparta) d i rec t Tannersville, Pa., VORPAC, d i rec t Westminster, Md., VOIFAC, Jet Route 48 P*>?.aski, d i rec t Tri-City.

After the aircraft was clear of t h e terminril area, a climb was

Echo Lske Eleven Standard I n s t r m e n t Depart-ue - (radar

made t o the assigned f l i g h t l e v e l (FL), 410. The a i r c r a f t entered the Washington A i r RoGte Traffic Control Center (ARTCC) area a t approximately E110. A t 2152, when t h e flight w 8 3 about 45 miles north- east of Pulasld, Virginia, control of t he f l i g h t was passed from the Washington ARTCC t o the Atlanta A R X C northeast high-altitude sector controller.

clearance t o descend f rom FL 410. The control ler cleare3 t1;- f l i g h t A t 2153, t he crew contacted the Atlanta AKPCC and rrauesterl

t o descend t o FL 240 and t o change t o transpondcr code 1400. ;.t 2157, control was passed t o t h e low a l t i t u d e manual sector controller. The f l i g h t was about 5 miles northeast of the Wzshington-Atlanta Cenker boundary, or about 20 miles nort:.dast of Fulaski a t t h i s time, and

M H z . A t 2157, they reported descending through FL 250. Wher the within 1 minute the crew was instr.xcted t o contsct t he Center on 120.0

f l i g h t reache-! a posit ion 5 t o 6 d l e s northaask of Pulaski, the p i l o t was i x t r u c t e d t o depart from the Fulaski VORIAC on a 250' heading f o r a radar vec-tor t o t he f i n a l approach course t o the "-City Airport. The crew ecknowledgcd. T h i s was followed. by a ~. cleerance for the f l i g h t t o continve descent t o 8,000 feet. The crew again acknowledged.

A 5 22_4:15,~ aft&z..several calls from t h e Atlanta Cezter, the crew~repl ied t o a query for t h e i r a l t i t u d e with; "Six JP out of two three, oh. " Atlwt.q$entsr ~.cknow&e!ge.uit~ .L??Qsc,. report leavfng one seven thousand. The crew acknowledged wit!,, "Six JP:~"' FiYerX- Were no fur ther transmissions fran the f l ight . The'radar controii& said he observed the t a rge t of the a i r c r a f t on Lis radarscop(. as t h e

All times used herein are expressed i n eas tern stan3ard time, based on the 24-hour clock.

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a i rc ra f t contimed on couI'&e, hntl a t approi[L~tcly.2209:20 the t a rge t of the a i r c r a f t hi sap pea red^ froa the radarscope. The c o n i r ~ ~ - - - estimated t h a t when the p i l o t reported leaving X.230, the-&Fsraft was 7 or 8 miles nortileast of Sugar Grove Tntersection, which-* located appxiximately k> miles f i m t h e s t of ' the Pulaski-VO-. lie estimated that t h e t a rge t ,disappeared from.€he-.raTG?%mijaba& 3 miles west of t h e posit ion where the crew reported out of X 230.

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Witnesses located between 2 and 4 miles norttleast of Mountain -

&mire Airport, R u r a l Retreat, Virginia, steted tha t on the night of the accident they heard the noise of a j e t flying over, followen by a sudden thud t h a t shook floors i n some houses. They estimated tha t t h i s occwred about 2210. They described the night as dark and said t h a t the sQ was overcast. They were unable t o see t,he aircraft and could not determine t h e d i rect ion it was f lying or i t e location when t h e noise stopped.

looking f o r t h e a i rc ra f t , tho owners of a fam found the wreckaEc while they were checking the i r livestock. They notified the Virginia State Police who arrived on the scene a t apprximately noon. The geographic coordinates of the accident site are:

About ll55, November 1, while search par t i e s were i n t he area

l a t i t u d e 36" 55' 15" N. longitGde 81" 18' 50" W.

Thio posit ion is on a bearing of WkC at a distance of about 10 nautical miles from Sugar Grove Intersection.

1.2 IMuries t o Persons

InJur ies Crew Passengers Others

Fa ta l 2 Nonfatal 0

1 0

0 0

None 0 0

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1.3 Damage t o Aircraft

d m at t i tude. The impact c ra te r i n the sof t ground measured 25 feet i n dlaneter and approximately 18 feet i n depth. The distance

was 9 feet. The locse earth concealed 801119 l s rge boulders and most from the top of the c ra te r t o t h e top of loose ear th i n the c ra te r

of the heavier a i r c r a f t ?mponer.ts. &c-ept fo r a few b i t s of metal, the only lare- piece of the elrcraft that was v i s ib le i n the c ra te r yR6 the l e f t aileron. &tenSivr f ramenta t ion of the aircraft Bad

the cra ter on a hearing of 170' for a distance of about 500 feet. occu?ed, leavinti b i t s and pieces of metal around and foward of

The largest pieces of wreckage outsiae of the crater were the control surfaces, r igh t landing gear, and broken wing panels. Sane heavy cwponents, such as the engines, moat of the empennage, and the l e f t landing gear, were b u r i d i n the crater. All principal pa r t s of the

The aircraft struck the ground wings level while i n a 60' nose-

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wing and t a i l surfaces were found a t +he accldent site; however, the landing gear doors were found 2.43 nautical miles from the accident s i te on a bearing of 314".

1 .4 Other m a = - The impact occurred on an open pasture t h a t i s adjacent t o Virginia

Sta te Road 6l'l. The l e f t wing damaged a wire fence between the road shoulder and the c ra te r . Several small trees were broken off a t the base of the trunks by the a i r c r a f t .

1.5 C r e w Information .. G- - - J The P i t t s ton Company for 6 years. He held a i r l i n e transport p i l o t c e r t i f i c a t e No. 44047-40, wi th type r:+.ings i n the Aero Commander ll21

76:5G hours i n the last 90 days and 2:3: hours i n the 24 hours prior and the E-3. He had a t o t a l f lying time of 7255:lO hours, including

t o the accident. His to ta l time i n the ll21 was 7 p : 2 5 hours. His

and b3:05 hours of simulated instrument f l i g h t . His most recent f irst- instrument time consisted of 695:5O hours of actual instrument f l i g h t

with the l imita t ion t h a t correcting glasses be worn while f lying. The c lass airman's medicel ce r t i f i ca te was issued on September 27, 1969,

only evidence of glasses found i n the wreckage area were the frames 9f the p i l o t ' s sur.glasses. These were i n t h e i r case and were 1-ocated apprcaimately 200 feet forward of the c ra te r i n mud.

Captain Robert Joseph Quint, aged 48, had been employed by

Post-mortem examinations of the crew vere not performed. The p i l o t ' s Federal Aviation Administration (FAA j medical ce r t i f i ca t ion records were reviewed back t o 1965. There was no documentation on any FAA form records during t h i s period t o inZicate that the p i l o t had consulted a phycician f o r a medical complaint.

Mr. Quint re t i r ed from the United S ta tes A i r Force (USAF) i n 3.963.

prior t o 1!%5, and a review of thnse records showed thz: after mil i tary His medical records were obtained from the Air Force f o r the period

retirement, medical care was sought for b i l a t e r a l t i m i t u z (ringing i n the ears) a t LnSry tlPB Dispensary and a t Fi tzs imons General L P q i t a l .

he related a 3 week history of t inn i tus with no his tory of vertigo. He was fir& seen for t h i s complaint in November 1963, at which i:?~.?

t h i s complaint on January 27, 1964, and reported no improvement a t He was treeted with Arlidin and nicot inic acid. He was last seen for

tha t time. There was a history of progressive b i l a t e r a l hearing loss i n the high frequencies since 1952. There is no record of s ignif icant medical conplaints after J a n u w - 27, 1964. His vision defect consisted of a d i s tan t vision reading uncorrected of 20/jO, corrected t o 2O/15.

Copilot Walter Jul ius G i l l y , aged 38, was employed by The P i t t s ton Cmpany i n June lN8. He held private p i l o t c e r t i f i c a t e No. 138gce, with a i r c r a f t single-engine land rating. He was not instrument rated.

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He had a t o t a l w i n g time of 421:lO hours, of which 227:3O were as

t o t a l f lying time during the l a s t 90 days was &:25 hours as copilot, copilot and 75:40 as th i rd cr?man i n the Aero Commander U21. H s

of vhich 2:35 hours weye flown i n the 24 hours prio.- t o the accident. There is no record of any instrument time, ac tual or simulated. His most recent second-class physical was is-ued July 22, lm, w i t h fhe l imitat ion thst ccrrecting glasses be worn while flying. He held Aircraft and Powerplant Mechanic Cer t i f ica te No. 1388935.

1.6 Aircraft I n f o n u a t .

N23& was an Aero Commander Mcdel lI.21, seri-1 '1,: .**+L 0-

accumulated a t o t a airworthhess issuance date of October 27. 1067.

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~~ .. ._ ~.._~.. 1 of 746:45 hours'operating time s:nce new. The two

_ . , _ _ ., . The a i rc ra f t had i P General E1ectrj.c ~ 6 1 0 - 1 engines ins ta l led i n the a1rcra:t had accu-

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lated 74645 h m s of operating time slnce new. According t o the craf t records, the l a s t periodic ihzpection was performed on

October 24. 1969, at which time the Bos. 1 and 3 main bearims i n

1

i rdr mu

. . .. No. 2 engine were replaced, end minor foreign object damage vas repaired. A hot-section inspection was conducted on both engines. The t o t a l time on the a i rcraf t and engines cn Octoher 24 was 733:30 hours.

The a i rc ra f t record6 showed that the required inspections had been

had been corrected. Service bul le t ins and service letters had been performed at prescribed time in tervals and nonroutine maintenance items

complied with, except for Service Bul le t in J-7. This bul le t in pertains t o the ins ta l l a t ion of f u e l shutoff valve sui tch guards and inspection of fue l supply l ines .

N236Jp was cer t i f ica ted for a maximum gross takeoff weight of 17,5CO pounds. Th* file1 capacity 9 6 gallons. According t o fuel- ing records at I;Guardia, 400 gallons or* f u e l were added before the

however, the p i l o t showed 2 hours and 30 minutes of f ie1 on h i s f l i g h t last fllat. The t o t a l f u e l aboard a t takeoff could not be determined;

plan. According t o P i t t s ton Company p i lo ts , t h i s is a standard fue l

740 eaUons, or 5,000 pounds. 2f Bssed on a f u e l consumption r a t e of about load for the flight frcm LeGuardia t o l'ri-City and smmtnts t o about

a t the time of t he accident. 300 gallons per hour, it is estimated that about, 303 gallons remined

1.7 Meteorological Information

According t o witnesses. the weather i n t h e Rurd hetreat area a t the time of the accident was raiJy and fogey wi t11 low clouds. Saie wltneases reported strong winds between 2200 and 2300.

Surface weather charts issued by the U. S. Weather Bureau showed en occluded f ron t extending 6011theastnud frcm soutkeastern Minnesota t o western Kentucky, and then southwestward t o the Oulf of Mexico.

&sed on 8 weight of a standard U. S. &on of kerosene o r 6.75 pounda.

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I n advance of th? f ront , including the accident site, extenslve areas

ra in . A t the time of the accident, tht%se prefrontal conditions had of multilayered clouds were reported, wixh intermittent, mostly l i g h t

advanced as far eastward as Bluefield, West Virginia, ar.d Greenville, South Carolina. Overcas: cloud conditions were being reported by o f f i c i a l weather observation s ta t ions a t bist.01, Tennessee; Bluefield, West Virginia; Xickory. North Carolina; Roanoke, Virginia; Greensboro, North Carolina; and other s ta t ions t o t h e nt r th , west, and south of the accident s i te .

i ery moist air from a:?ouc 21,000 t o 30,000 feet m.s.1. and saturated The 1900 bnt ington. , Wes: Vrrginia, radiosonde ascent showed

conditions axout 23,000 feet , with high moisture content a l so indicated f r o m 6,000 t o 9,OOC f e e t . The freezing l eve l was a t 8,800 feet m.s.l. The 1900 Nastxille, Tennessee, ascent showed high moisture content a t all l eve l s frcm near 5,009 f e e t t o above 25,000 feet with saturated air from 6,000 t o 16,000 feet. The freezing l e v e l was at 8,700 feet m.s.1.

The Weather Burer.11 forecast available prior t o deprrture from LaGuardia called, i n par t , f o r occasional moderate o r greater clew., air turbulence i n a laycr 25,000 to 40,030 feet, as well as f o r occasional moderate turbulence below 9,000 over the mountains of southwestern Virginia. lke forecasts called fo r layered clouds with tops up t o 18.000 feet over western Virginia. A t 1845, thc Weatlfer G-eau at LaGuardia provided a pref l ight weather br ief ing fo r ~tfie flight of N234T.

1.8 Aids t o Naviqation

Pi taski VaKPAC is located approximately 89 naut ical miles from Tri-City Airport on a bearing of 070". The vector of 250° from Pulaski lies approximately halfway between Victor Airway 16 and Victor Airway l C N , passin& a mile south of Momtain @pire Airport and 4.5 miles north of the Sugar Grove Intersection.

The Atlanta radar s i t e for the northeast lar a l t i tu+% sector i s located m t Lynch, KentucQ, about 78 na,ltical miles west of the accident riite. The antenna ro ta tes a t 6 r.p.13. MTI 1/ circui t ry is employed. On the date of the accident, c i rcular polarization was used. The radar display was on t h e 150-mile range, centered.

1.9 Commnlmicatians

There were no reported problems with ccrmnunications.

1.10 Aerwirome and Ground F a c i l i t i e s

Not involved.

1.U a j h t F.ecorders : ' None ins ta l led nor required.

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1.12 Aircraft Wrrckaee

There was a "V" shaped depression on e i the r s ide of' the crater, perpendicular t o the l i n e of f l igh t . The depression on the :eft side of the crater, looking toward the di rect ion of i l ighc, extended .mto the shoulder of Sta te Road 617. The distance between the ends of

long piece of the balance weight and ekin from the leading edge center of these depressions was 43 feet . The left depreseion contained a foot-

t he l e f t aileron. The cra ter wall and the sides ol' the two depressions away from th? di rect ion of flieht (north) were i n l i n e with t h e broken branches of a tree, forming an angle of 60" t o th2 horizon. The eleva- t ion a t the point of ground impact is 2,450 feet m.s.1.

The Wreckage was almost equally distributed about 200 f e e t on ei ther side of t h e wreckage path for a distance of 500 feet forward Of the main impact center. Pieces from the left wing and l e f t side of t h e fuselage were genera.@ on the left of t h e vreckage peth center- l i n e and, correspondingly, pieces from the r igh t s ide of the a i r c r a f t were found on the r i g h t of t he wreckage path. A crane and a power shovel were used t o remove wreckage ??.om the cra ter .

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The major components found i n t'ne crater were t h e two engines, the l e f t landing gpar, and 'the major portion of the empennage. Their position i n the c ra te r correspondled t o t h e i r positions on the aircraft Prior t o impact. The r igh t lending gear, r igh t ai leron, and a portion of the r igh t wing inboard aft of the main spvx were located a few feet t o t h e r i g h t of the c ra te r .

It is estimated tha t 99 percent of the az rc ra f t was recovered. Most of tine engine instruments and some f l i g h t instruments were located dong the center of the wreckage path up t o 9 0 feet from the crs ter , i n and on both sides of a creek. Examination of the a i r c r a f t componentt. revealed the following:

Structures

a. Fuselage. Wings, and Fsopennege

There were no indications of major in- f l ight fltructural failure.

b. el' Surfaces

Erost of the fuselhge, wings, and empennage were recovered.

Inspection revealed impact failurg a t the attaching points and impact dawge on t h e leading edger.

All of the control surfaces were recovered a t the crash site.

.c. Control Cable Torque Tubes and Quadrants

5463001-19) had an area of high polish and indications of mul- The right elevator reducer tube bearing surface (Part No.

t i p l e s t r i k e damage from the inner race of the bearing (Part No.

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KP21Bs). (ServicP Bulletin J-6 had been accomplished on thin aircraft. )

system did not disclose evidence of any in- f l ight malfunction or failure.

d. Main Landins Gear

Reconstruction and exemination of the remaining control

I 1 ) The main landing sear up-locks were recovered undamaged.

i n f l i g h t and were located approximately 2.43 miles from the 2) The main landing gear doors separated frmn the aircraft

Crash Bite. The two doors were about 300 feet apart. ( 3 ) The f o w main landing gear actuat.or8 received extensive

This corresponded t o a landing gear w s i t i o n between extend- impact damage with the plstons i n a midcylinder position.

cd an3 retracted. (4) Impact damage to the wheels and brake disc assemblies was frw a Sone against the inside fro& of each wheel.

e . Nose Landing Gear

t h e area of the trunnion mount, and the inner cylinder was inserted i n t o the outer cylinder up t o the axle.

f . Speed Brakes

The nose Eear stmt assembly outer cylilrler was s p l i t open i n

at tile actuator rcd eye. The actuator w 6 n found i n the extended position.

The lef t speed brake separated a t t h e plan0 hinge area and

The r i g h t speed brake a lso Separated a t the piano hinge area and at t h e actuator rod eye. The actuator was attached t o the

i n a near fully re t racted position. Tin5 speed brakes are e l e c t r i - spar and the cylinder was s p l i t the en t i re l eng th , w i t h the piston

c;illy actuated and hydraulically operated.

g.

two actuator cylinders were separated, both frm the f l aps at ':he rc4 eye and at the spar attachmeat. The cylinders were un- damaged and the pistons were found i n the .-etracted position. ?his corresponds t o the flruy re t racted f laps poaltion.

h. Trim

The flap surfaces were found i n .the main wreckuge area. The

and wbs observed t o be i n a faire3 position. (1) The ai leron tab was still attached t o the l e f t a i leron

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symmetrical impact damage on the leading edge. (2) The rucider tab '.,as separated' completely but received

frm the horizontal s t a b i l i z e r at impact and the actuator (3) The horizontal s t a b i l i z e r trim actuator separated

was attached t o a p a r t of the fuselage structure. The eye of the r i g h t actuatcr rod end was s t i l l nttached t o the horizontal stabili7.er. The r igh t actuator was reas- sembled and the phyeical measurement between the centers of the a t tach points was 15.56". Noseup t r i m l i m i t is

The angular relationship of the t r im limit svitchen va5 13.99 ,+ .OK" and nosedown trim limit is 16.12 2 .OX?".

measured. From this it was determlned that the s t a b i l i z e r trim was positioned at apprcaimstely zero degrees on Inpact (neutral) .

Systems

8. Hydraulics

was available i n the primary hydraulic system a t impact.

b. Electrical/Electronics

Inspection of the hydraulic cylinders indicated that fluid

by impact; however, examination of the recovered components revealed the following:

Most compnents of both e l e c t r i c a l systems were destr3yed

(1) The r igh t d,c. 4/ generator and drive shaft d id not indicate that any malfunction had occurred pr ior t o impact. 2) There was no evidence of an e lect . r iaa l short or fire.

powered by t he No. 1 d.c. bus, showefi. evidenct! of extensi..e 3) The filament of the a i r c r a f t t a i l posit ion l i g h t ,

elongation damage i n two direct ions while i n a duc t i l e state. (4) Two of the six 28 v.d.c. 5/ operated. renote control c i r c u i t breakers (RCB'S) were found. Demage showed they were i n the energized posit ion a t impact. (5) The 329B-7A Flight Mrector Indicator and t h e 33.m-6A Course Indicator used :n the FD108 received extensive impact damage. Tkese units were tnken t o the Collins

The following information was disclosed during disassembly: Radio Company plant f o r disassembly and inspection.

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Collins 329B-7A Flight Mrector 1nd.dicator - the mechanical a t t i t u d e display was i n t a c t and vis5bl.e. The indicators were jammed i n the followirig poaltions:

Bark Attihcie - 20- right-wing-dam ( t h i s presenta- t i o n w i l l result i f 115 v.a.0. apower is removed with the s i r c r a f t i n this a t t i tude) .

,

'41 d.c. - di rec t current. !

v.d.c. - vol ts d i r e c t current. v.8.c. - vol ts alterrxiting current. i

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Pitch Atti tude - 90" pitchup ( the indicator w i l l move t o t h i s position w i t h loss of 115 v.a.c. pcuer). Mode selector switch - "IIeaaing." Remaining displays, including p i t ch coolmsnd knob, g l i d e slope pointer and f l sg , local izer pointer and flag, (iyro f lag, compltter flag, inc l inmete r , and camnand bars, were either canpletely missing or so b a a v deforme* t h a t no r e l i a b l e indications were present.

Collics 33m-6~ Course Indicator - the displays were bad ly deformed and the azimuth card was missiw. M s - assembly inspection indicated the foliowing: .

Course Selector Indicator - 225O. Heading Selector Aircraft IIeading

- aboat 250' magnetic.

Mstance Measuring Equipment. (DE) - 48 naut ical - about 235' magnetic.

miles. (6) Tte copi lot ' s Sperry GKLW v e r t i c a l gyro (Part No. 2585618-400) was indicating wings l eve l and approximntely 60' nosedown a t impact. This gyro i s self-ccntained and

77) The Copilot's Course Indicator (Collins 3 3 m - j r ) revealed the following:

owered from the No. 2 8.c. bus.

Aircraft Heading - 23C0 t o 240' magnetic. Course selectee - between 225' and 250' magnetic. NSV f l a g - appearea t o have been in t he window.

Poverplants

Both engines had sustained extensive fragmentation, and no

Tho bullet nose8 of both engines wcre evenly displaced axially component. wae considered suf f i c ien t ly whole t o submit for test.

x*e~uwa*u'd. The compressor center l ines of both were displaced upward w i t h respect t o the turbine centerl ines with the No. 1's dioplncemcnt approximately 5 inches and the No. 2's approximately f'i i ~ ~ c l m ~ . Hx-izontal displacement was not evident on the major auoombly alignment.

kinl ccr,pression was extensivo primarily in the combustion CUSP reirlors with the No. 2 engin(! most severe w t t h the turbine can) cmprcsoed through the combustion case t o the plane of the aft f L a w of t h e main frame. Neither engine shoved evidence of external fire or hot o p t s .

Elect r ic can pa^' who concluded t h a t both engines were at a povv state of approximately f l i g h t id le , when impact occurred, and tha t there wali no evidence t o indicate other than normal engine operating capabili ty.

fl a . ~ . - u t e r n a t l n g current.

Tho engines were examined by representatives of the Geaeral

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t he wreckage path wherein sane were impact frozen and were P s r t of the engine instrumcnts were recovered along

readable as follows:

percent, r.p.m. (1) Right and left enpine tachometers indicated 57

s l i g h t l y less than 400' C. (2) One exhaust gas terrperature indicator needle read

(3 ) *do f u e l te:;perature g;?ges indicated plus 4" C.

20 p.s.1. (4) One f u e l pressure gage indicated approximately

(5) One engine o i l temperature gage indicated 50' C.

Fuel - of ewth beneath the south w a l l of the c ra te r . I n addition,

were saturated with kerosene. t h e st,ovelsful of mud taken from the bottom of the cra ter

A coroiderable amount of kerosene was found i n a pocket

1.13 Fire There was no evidence of in- f l ight or ground fire,

1.14 Survival Aspects

This was a nonsurvivable accident.

1.15 Teats and R c s - d

the vic ini ty of the crash cite, using a helicopter and a mi!.itary J e t a i r c r a f t . The purpose was t o determine if the radar controller on duty the nif;ht of t he eccident could confirm the posi t ion OF t he a i r c r a f t i n re la t ion t o Sugar Grove Intersection, when the p i l o t reported descending through FL 230 and when the a i r c r a f t disappeared from the radar screen. The control ler ' s best revised estimate placed t h e aircraft about 1 mire southeast of the Mountain Empire Airport at FL 230 and about 3 miles west-southwest of the airport when it disappeared from the radarscope. The la t ter pocition is 4.5 miJ.es southwest of t he accident site.

Radar tracking f l i g h t tests were conducted on November 17th i n

Radar contact could be maintained on the ffiilitary j e t transponder target above 4,800 feet m. :.l., both climbing acd descending.

A dets i led system am'ysis was conducted t o determix? if p i t f a l l s

would result i n loss of a t t i t u d e information t o the pilot. The system existed i n the t o t a l aircraft e lect r ical /e lect ronlc systems, which

was found t o be extremely complex, with backup capabili ty equivalent t o that of a camerc ia l transport . !

EktencIve Jet Comander i l i g h t Simulai?F test0 and tvo scparate flight twts =ere conducted i n an effnr t t o r#?veal aw obscL-e defiriencies i n the e lect r ical /e lect ronic systems and t o cileck f l i g h t characterist ics

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of the aircraft. It w a 6 determined that the aircraft w i l l reach or exceed the limiting eirspeed/Macli numbcr rapidly, when the nose attitude goes 10' or more below the horizon. No surprise deficiencies in the electrical/electronic systems were disclosed.

1.16 Pertinent Information

It was learned from Pittston Company pilots +,hat the crew of N23fiJP was experiencing difficulty with the left 8.c. generator system

I when they landed at LaGuru'dia prior to the last flight. Xter landing, j

& tht copilot/mechanlc requested by a teiephone call. to another canpaw i 1 pilot/mechanic that he be met at Tri-City Airport, because the left

a.c. "generator-out" light had come on during the landing at LaGuardia. He said he didn't )mow if it was caused by a loose connection or by a shhft failure, and, if reqxired, he wanted some assistance and a swciai

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wrench with wNch t o remove the.generator when the flight arrived it Tri-City Airport.

to provlde essential l l 5 v.a.c. power to the pil3t's essential flight instruments in the event the aircraft a.c. power syatem failed. The

bus. The pilot's radio essential bus is normelly connected to the otatio inverter is powered by 28 v.d.c. f m the pilot's radio essential

battery bus, but can be shifted to the No. 1 d.c. bue. The Sta',io inverter povides 115 v.a.c. to the pilo+,'n Flight Mrector System, the 26 v.a.c. instrument transformer and the other essential 115 v.8.c.

maintained as long a8 a w 28 v.d.c. is available in the aircrafc. requi?enients. The pilot's Flight Mrector Systero operation can be

This aircraft wac equipped with a 250 v.a. a/ static inverter

generator tokes over automaticauy, providing the faulty generator switch remains "on." Either a.c. generator is capable of carrying

If the left a.c. generator fails and that generator switch is turned the entire a.c. load at approximately 80 percent of generator capacity,

"off;" the static inverter switch must then be turned "on" to get a.c. power to the pilct's essektial flight instruments.

constant frequency bv3. This instrument cannot receive 8.c. power from the stutic lnverter but must receive a.c. power -om anopcratxx a&. generator. The tittitude information on this gyr0.i~ reliable for 8 period of 5 to 7 mtnutes after the removal of all ll5 v.8.c. electrical power. Examination showed that this instrment was 61s- playing an uccurate indication at impact.

In the event of failure of either a.c. generator, the other a.c.

The copilot's vertical gyro is powered by the No. 2 115 v.8.c.

2. ANALYSIS CONCLilcIONS - 2.1 h ~ I I i 6

An evaluation of a l l .the evidencs.lndicates that the crq. . mrienceba loss, o f . e l e . c ~ ~ ~ ~ ~ ~ ~ . ~ ~ ~ ~ . ~ ~ ~ ~ ~ e i r last transmiseiori and the aircraft cra6hed apprcximateu 1 minute hter* ..~ . ~ .

& v.8. - volt empere. 1 ' a

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The last transmission from the~crew vas a t 224:15, wher they reported descending through FL 230. The redar controller, watching the a i rc ra f t ' s progress on h i s radarscope, observed the disappearance of the radar t a rge t a t 2209:20 a t a location approximately 3 miles west

point at which the target. disappeared i s 3 t o 4 miles west or t o the of the point where the c r m reported descending through FL 230. (The

Tri-City.) r igh t of the track the a i r c r a f t was making gocd between Fulaski and

The cmputcd angle of impact at which the a i r c r a f t struck the \ ground was approximately 60'. This angle coincides with the reading 4 on the copi lot ' s Sperry G U C e v e r t i c a l gyro, whlch indicated wings

l eve l and 60" nosedarn a t impact.

The loss of e l e c t r i c a l power occurred while the aircraft WLS on

The p i l o t ' s >:light Director Indicator (?DI) showed a p i t ch a t t i t u d e of a ?leading of approximately 235" as indicated on both 4irectional gyros.

90" noseup. Ti& is the...rs_ultant ur I s removed. It a lso shoyed a 20' rig-n a t t i tudg. ' 'The FDI

o w!len 115. v.8.c;~ power

will retain a 20' right-wing-down 'attitude if U5 v.a.c. power is removed during a 20' r i g h t bank. This failure of the Fl ight Director System ( F E ) indicate6 that it was not receiving power fXm e i the r a.c. generator bus or from the s tat ic inverter.

would norwdly not present a problem because the other a.c. generator Failure or malfunction of onea.c.generator while i n f l i g h t

w i l l autcmaticnUy take over t h e entire 8.c. e l e c t r i c a l losd, provid- ing the foiled generator's switch is not turned off.

LaGuardia. The reason for the apparent malfunction is not known nor The le f t generator-out l i g h t came on during the landing at

is it .known if the left generator was functioning a t takeoff. Had the crew d e w t e d v i t h an inoperative left eenerator and subsequently

aware of the S m c e of trouble and would most l i k e l y have turned on experienced a failure of the r igh t generator, they woula have been

the s tat ic iCverter t o regain power on the f l i g h t instrume!k3. The system i s desitmed so that i n the event one a.c. generator fails ur malfunctions, the other a.c. generator assumes the e n t i r e a.c. load, provided the Switches are le f t on. If the l e f t a.c. generator-out l i g h t came on, indicating a failure, and the crew turned off the lef t a.c. generator switch, the r igh t a.c. generator would not assme the load. However, the s t a t i c inverter would supply a.c. power t o the Fl ight Director System, providing the s t a t i c inverter switch was turned on. ?he f a c t t h a t the FDS was not get t ing power from e i the r o l t h e +c .-generators or the static 'irivert%r idicates: (1) a fe.ilure of '&-%Wee p m r s O w c ~ e 6 ~ t-lat the crew mie-

left R . C . peneracor oFb5th- lEiTand ~~~.~~ r igh t a.c. ~~.~~ geuerators. A failure Of a l l three power sources.~is most unlikely. .~. , .. - ..

w a g e d the eica-f-- .r%uzs.-cCcieheftne . .. .. ~. . ~..

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The s t a t i c inverter is m e r e d by 28 v.d.c. from th- essentia l bus. Normally, t h e p i l o t ' s radio essent ia l bus is connected

radio

t o t.he battery bus, but it can be shif ted t o the No. 1 d.c. bus. The

System, the 26 vfra.c. i n s t m e n t transformer, and other essent ia l Gtatic inverter provides ll5 v.a.c. t o the p i l o t ' s Flight Director

115 v.a.c. requirements. The signiflcance of t h i s is t h a t the p i lo t ' s FIE operatlon can be maintained as long ae any 28 v.d.c. is available

5 i n the a i rcraf t . The extended speeZ brakes, the t a i l position l i g h t , and the remote c i r c u i t breakers (RCB's) all indicate the avai labi l i ty of a 28 v.8.c. power source.

I

The copilot 's Sperry GHLCe ver t i ca l gyro receivep paver from t h e

This ins t rmen t was indicating properly a t impact; havever, it w i l l No. 2 arc. bus and does not receive a.c. paver fim the s t a t i c inverter .

proviee re i i ab le ii66iiXiori~for~ 5~ to-~'f-mi&iEe< if electrical power is suddenly removed. this^ 1ndIcates.tbet atLleast one of the two a.c.

power f a i l u r , e . , . o ~ ~ - ~ ~ ~ . 3 h o r t ~ , befcv Impact.- Failure of both a.c. generators was functioning a t the mment of impact or the to ta l - .&c,

generators and the s t a t i c inverter is considered highly iem6te i n view of (1) the lack of any indications of other than normal f l i g h t up t o the crew's l a s t transmission t h a t the a i r c r a f t was descending fhraugh FL 230, and (2i ' t i .e e l e c t r i c a l systems are independent OP each other and provide redundancy of operation.

. . . . ~ ....,...

direct ional gyro information at the same time, since r:ach instrument The p i l o t ' s and copilot 's course indicators l o a t compass and

displqyed a heading of a p p r o x h t e l y 235" when disassembled. This c m w e s w i t h an ac tua l heading a t impact of approximately 170". This a l s o indicates t.he l o s s of the 26 v.a.c. reference voltage t o

reference voltage receive e l e c t r i c a l power fraol the No. 1l l5 .v .a . c . the indlcatars i n f l i g h t . The 26 v.8.c. transformers supplying the

constant frequency bus.

t u r n on ent i- ic ing equ ipen t . This addit ional e l e c t r i c a l load yay No-L procedure prior t o penetrating c l o A conditicns is t o

have been e.?ough t o fsil an already malflmctionLng a.c. generator or it may have overloaded a single functioning a .c . 'generatar, cawing it t o cut 0 3 . Had t h e former occurred, no eme~-gency wodd have exlsted; hovever, the crew mlght have suepected tha t one existed and turned off the switch of the fa i led generator as a corrective neasure. Tills action would have removed 115 v.8.c. power frcm the FX. O n the other hand, if one generator were Inoperative and the other kscamc overloaded end cut off, it is conccivable that the crew m i g h t h.ave l o s t control af the a i r c r a f t whj.le attempting t o res tore power.

which was already i n a paver wen€-ofY, went A lose of control that the air_c_raft,

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ln_to,..a.~hi&h-speed dive t o the r i g h t from which t h e p i l o t could not recovcr without initrument reference.

2.2 Conclusions

( a ) Findings

'I 1.

b 2.

3.

'r.

5 .

6.

7 .

a.

9.

10.

11,

12.

The crew was properly ce r t i f i ca ted for the f l i g h t involved.

The aircraft wss properly ce r t i f i ca ted .

The veight and balance and center of gravi ty of t h e a i r c r a f t were within l imi ta t ions a t departure *ore LaGuardia and a t t h e time of t h e accjdent.

Weather condit ions near the accident site were IFR v i t h layered clcuds ~2 t o 18,000 f e e t and l i t t l e or no v i s i b l e horizon above t h a t a l t i t u d e .

There was no fire i n f l i g h t nor on the ground.

There was no s t r u c t u r a l f a i l u r e during t h e f l i g h t other t h a n the l o s s of landing gear doors.

There was no malfunction or failure of t h e f l i g h t con t ro l system.

There was no evidence of crew incapaci ta t ion although no post-mortem exminat ions were conducted.

The le f t 8.c. generator mslfunctioned or became inoper- a t i v e i n f l i g b t .

I ' ilectrical parer was not continuounly supplied t o the &lo t ' s ( cap ta in ' s ) e s s e n t i a l f l i g h t Instruments, part icullarly t h e P1i.ght Director System. This could have been accomplished by: "

a. either leaving the l e f t generator switch on, thus allowing t h e r i g n t generator t o assume. t h e load;

b. or, if t h e l e f t generator switch is turned off, turning on t h e s t a t i c inver te r switch.

A t the time of the 8.c. e l e c t r i c a l power loss, t h e air- craf t was i n a 20° r i g h t bank.

The a i r c r a f t impacted t h e gronnd with the engines a t i d l e Power, the speed brakes extended, and t h e landing gear P a r t i a l l y extended.

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13. The aircrRft turned r i g h t approximately 280' and descended from agproximately 18,000 feet above

evidenced from the posit ion of the landing gear the erouad in the last minute of f l i g h t , as

doors 2.4 miles northwest of the crash site.

14. Thc p i l o t attempted t o slow the a i rcraf t and regain control during the dive by reducing power t o id le , extending t h e speed brakes, and lcwering the landing .gear,

(b) Probable Cause

The Board det-mines tha t the probable cause of t h i s

W - v o l t a l ternat ing current e l e c t r i c a l system, the crew accident w a s that, following a malfuuction .o r~f&iu i -e~~~in the

d i d not take proper action, r esu l t ing i n the.Joss of the p i l o t ' s f l i g h t instruments in i n s t r m e n t flight"'coiidi€Tons and subsequent loss o f control . -

3. RFCOWBXDATION

is changing the emergency procedures section of the Jct Colnmander As a result 01' t h i s investigation, Colmncdore Aviation, Inc.,

f l i g h t manual t o provide a warning t h a t t h e generator switch of a failed generator nust s t ay i n the "ON" posit ion t o maintain the automatic load transfer function.

This accident points up the need fo r ovners and p i l o t s of air- i c r a f t t o be informed of the i n s t a l l a t i o n aild u t i l i z a t i o n of complex avionics equipment. Aircraft maintenance d flight manuals should be updated by supplemental documentation whenever avionics modifica- t ions are made t o the a i rcraf t . This is not now being done on a st.crndardized basis. Act ivi t ies i n s t a l l i n g supplemental type certifi- i ca te ( S W ) mcdificationa should be required t o provide the owner of the a i r c r a f t with appropriate instructions for t h e proper operation i and maintenauce thereof.

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The Board, therefore, recamends that:

The Administrator, Federal Aviation Administration, take necessary action to 3ssw-e that all avionics modifica- tiona to aircraft, ti& their proper use, be documented as amendnents to the maintellance and flight manusla and that this information be disseminated to aircraft m e r 6 and pilots.

By THE NATIONAL TRANSPORTATION SE.FETY BOARI):

/a/ J@HN n. REED Chairman

/S/ OSChR M. LAUREL i i I 1 1 i

Member i

/ s / FRANCIS n. MCADAMS Member

- /S/ LOUIS M. THAYER

Member \

September ‘9, 1970.

AppENmx

INVESTIGATION AND .KEARING

1. Investigation

The Board received notification of the accident at appraximately 0940 e.s.t., on November 1, 1969. The Investigator-in-Charge was dispatched immediately to the scene from the Washington Field Office

Washington, D. C. Working groups were established for operations, at Dulles International Airport with technical assistance from

witnesses, structures, powerplants, aircraft and maintenance zecords, systems, and h-man factors. Parties to the investigation were

Compaw, the Federal Aviation Administration, Commodore and General Electric Company. The on-scene phase of was completed in about 7 days because of fragnenta-

tion of the aircraft and the need for utilization of a crane and shovel

analyses were continued for several months thereafter at headquarters in the salvage operatlons. Extensive tests, research, and failure

and other locations.

2. Hearing

There was no public hearing.

. ..